About mswx

If you're tired of inaccurate weather forecasts because you live in this little microclimate up here, this app's for you.

How does it work?

Two composite stations do the heavy lifting:

• MSWX — the plateau. The five neighbor-owned personal weather stations on top of Monte Sano, combined every minute: drop the highest and lowest readings, average the middle three. That's the "Monte Sano" temperature shown across the site.
• HSVWX — downtown. Same trimmed-mean recipe, but built from six PWS clustered around WHNT's downtown studio in the valley. That gives a real "valley" reference, so the site can show how much colder/warmer the plateau is right now — not just against the airport, which sits way down in the valley and reads differently.

For forecasts, mswx pulls public model output for the plateau's exact coordinates — NWS, Open-Meteo's ensemble, Pirate Weather, and the HRRR. Then a bias correction adjusts each forecast point using five years of historical grid forecasts at this location compared against what MSWX actually measured on the plateau. The correction is keyed by hour-of-day, wind, and sky, so the model figures out e.g. that on calm clear nights the grid systematically underpredicts on the plateau (cold air drains into the valley, the plateau stays warmer) and applies the right offset.

How everyone else does it

Apple and Google get the forecast roughly right because they use your phone's coordinates. The "currently X°" tile is where the airport leaks in — there's no station on the plateau for them to pull from.

The pool

A sensor on the pool return plumbing reports the water temperature every 60 seconds, stored forever. mswx pairs that with the Monte Sano air-temp forecast to predict the pool water a week out — accuracy improves as more data comes in.

Spotting rotation on the radar

Monte Sano is a tornado-prone spot, so the radar map has a second view for storm season: storm-relative velocity. Tap Velocity at the top on your phone, or find it side-by-side to the right on a computer. Instead of how hard it's raining, you're looking at which way the wind is blowing inside the storm.

The Doppler radar over at Hytop can tell whether stuff in a storm is moving toward it (green) or away from it (red). Usually a storm is mostly one color — it's sliding one direction. But when a blob of bright green sits right up against a blob of bright red, that's wind spinning in a tight circle — rotation, the fingerprint of the spinning updraft that can drop a tornado. mswx subtracts the storm's overall movement out first (the "storm-relative" part) so the spin stands out instead of getting washed away by the whole storm drifting across the map.

Lightning on the radar

When a storm's overhead, the radar map drops little lightning bolts where it's striking, in two sizes:

• Bigger bolts — cloud-to-ground. The strikes that actually hit the dirt. These are the dangerous ones, and the reason the pool closes for 30 minutes after one lands within 8 miles.
• Smaller bolts — in-cloud. Flashes that stay up inside the storm. There are usually several times more of these; they tell you a cell is electrically charged up even before it starts hitting the ground.

Ground strikes come from the national lightning detection network (via NOAA). The in-cloud flashes come from the lightning mapper riding on the GOES weather satellite, parked 22,000 miles up watching the whole sky at once — ordinary apps only show ground strikes, so they miss most of a storm's actual electrical activity.

Color tells you how fresh a strike is. A brand-new one is white-hot, then cools through amber to a dim red before it drops off the map — ground strikes after about half an hour, in-cloud sooner. The bright bolts are striking right now; watch which way the bright edge is creeping and you can see the storm coming toward you or sliding away.

Tap the ⚡ button on the map to cycle how it's drawn: bolts → a softer glow (a heat-map of the in-cloud activity, calmer to look at when a storm is really cranking) → off.